Harvard Health Letter

Signs of early dementia

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Exercise can reduce the symptoms of mild cognitive impairment.

Top action steps to take when the doctor says it's mild cognitive impairment.

We all become a little more forgetful as we get older. But how do you know if you're experiencing the slight but noticeable change in thinking and memory skills known as mild cognitive impairment (MCI)? "The most common sign is a memory problem, and it's usually episodic, meaning that it's hard to remember events in your life, past and present," says Dr. David Caplan, a professor of neurology at Harvard Medical School.

Types of MCI

There are two types of MCI. One is amnestic, and refers to memory problems. Top signs include noticeable trouble remembering conversations, appointments, and where you parked the car. The second type, called nonamnestic, affects other thinking skills, such as language (you lose your train of thought during a conversation), attention (you have a hard time accomplishing tasks like bill paying), and spatial sense (you can't find your way around a familiar place). If any of these symptoms is happening more frequently, it's time to see your doctor.


Checking for MCI involves a physical exam to rule out any underlying cause of thinking problems, such as a lack of sleep. Your doctor will also consider your medical history and may order images of your brain. If a brief questionnaire gives weight to the possibility of MCI, a neuropsychologist may need to evaluate your thinking skills with a formal battery of tests. If MCI is the diagnosis, it doesn't mean your quality of life is over and dementia is imminent. "I have lots of patients who've stayed with one type of cognitive impairment that plateaus and never gets worse," says Dr. Caplan.

Take action

Several steps can help you make the most of your situation. Here are Dr. Caplan's top three recommendations:

  • Stay physically and mentally active. The evidence shows that these two activities have the biggest impact on thinking skills and can even reduce symptoms. Aim for 150 minutes per week of moderate-intensity exercise, such as brisk walking. And stay intellectually engaged. "Continue to work, or do something that requires mental effort: read novels or follow sports or whatever you're interested in, and pursue it actively," says Dr. Caplan.

  • Consider medication and testing. If you're diagnosed with MCI, you have a 50% chance of developing full-blown dementia. "We can do more testing of the brain to find out which 50% you're in, but there's nothing we can do to prevent dementia," says Dr. Caplan. "On the other hand, some medications may slow the rate of decline, and some may help the brain cells communicate better."

  • Plan for the future. It's a good idea to make plans now, while you're reasoning properly. "Update your will, and get an advance medical directive to guarantee your wishes are taken care of. Also, check out independent living facilities, so you know what your choices will be," says Dr. Caplan.